Fireplace supporting construction



March 22, 1966 J. v. NORTHWOOD FIREPLACE SUPPORTING CONSTRUCTIONOriginal Filed Oct. 1'7, 1962 2 Sheets-Sheet 1 INVENTOR. JOHN V.NORTHA/OOD ATTORN'YS March 22, 1966 J. v. NORTHWOOD FIREPLACE SUPPORTINGCONSTRUCTION .2 Sheets-Sheet 2 Original Filed Oct. 17, 1962 I NVENTORJail/V Y- NORTHIJOOD a J 0 3 I 4T 41 United States Patent 3,241,546FIREPLACE SUPPORTING CONSTRUCTION John V. Northwood, Lees Summit, Mo.,assignor to Sadie Miriam Northwood, Lees Summit, Jackson County, Mo.

Original application Oct. 17, 1962, Ser. No. 231,062, now Patent No.3,190,281, dated June 22, 1965. Divided and this application June 7,1965, Ser. No. 461,636

6 Claims. (Cl. 126120) This is a divisional application of my copendingpatent application, Serial No. 231,062, filed Oct. 17, 1962, now PatentNo. 3,190,281, issued June 22, 1965. This invention relates to fireplacesupporting structure and more particularly to supports for aprefabricated fireplace construction adapted to permit mounting incontact with combustible building materials.

Heretofore, lightweight prefabricated fireplace constructions formedsubstantially entirely of sheet metal have been devised; however, undersevere fire conditions within the firebox, the external surfacetemperature of the structure would increase to a dangerous level whichprevented mounting directly against combustibles such as wood studs orbeams in building walls,

The principal objects of the present invention are: to provide alightweight prefabricated fireplace construction which may be located incontact with combustible supporting building materials without firedanger; to provide such a fireplace construction having support memberscontacting combustible surfaces for mounting, which members arerelatively cool to the touch although high energy fuels such as charcoalor flashing grease are burning within the firebox; to provide supportmembers in the form of structural angles or channels extending outwardlyfrom exterior fireplace wall surfaces; to provide such support membershaving slots therein for inducing air circulation in the area of contactwith building combustibles; and to provide such support members whereinthe slots are staggered so as to avoid the possible insertion of stripstherethrough which would inhibit free air circulation.

Other objects and advantages of this invention will become apparent fromthe following description taken in connection withthe accompanyingdrawings wherein are set forth by way of illustration and examplecertain embodiments of this invention.

. FIG. 1 is a perspective view of a prefabricated fireplace constructionembodying this invention, particularly illustrating the supportingmembers for contacting combustible materials.

FIG. 2 isa vertical transverse cross-sectional view through the fireboxportion of the fireplace construction showing the mounting members incontact with opening forming combustible materials in a building wall.

FIG. 3 is a fragmentary vertical cross-sectional view through thefireplace construction taken on the line 3-3, FIG. 2, on an enlargedscale, particularly showing the supporting members in contact with upperand lower opening forming combustible materials in the building wall.

Referring to the drawings in more detail:

The reference numeral 1 generally indicates a fireplace constructionadapted for mounting in an opening 2 formed in a building wall 3 byflammable structural members such as wooden boxing studs 4 abuttingagainst wooden wall studs 5. it is to be understood that the opening 2may take the form of a common doubleung window casing (not shown) andthe building wall 3 may be an outside or inside wall without departingfrom the scope of this invention. The wall 3 has a finished interiorsurface 6 and an exterior surface 7 illustrated herein as havingexterior wooden shingles 8.

The fireplace construction 1 is mounted on and supported by the buildingwall 3 and extends through the opening 2 as best illustrated in FIG. 3.The fireplace construction 1 has opposed spaced sheet metal side walls9, a sheet metal bottom wall 10, a sheet metal back wall 11, and a sheetmetal top wall 12 together forming a solid fuel burning firebox 13, FIG.2. The walls 9, 10, 11 and 12 are preferably of aluminum coated steelsheets for strength without excessive weight and for resistance tocorrosion. The firebox 13 extends slightly forwardly past the buildingwall interior surface 6 and is there provided with decorative finishingmembers consisting of a hood 14, a hearth 15, hearth supporting chains16, and firebox front framing members 17. A deflector lip 17' is securedat the rear thereof to the central underside of the top wall 12 andextends forwardly and slightly downwardly to the front of the firebox 13where it turns upwardly into the hood 14. The hood 14 is locatedadjacent the firebox top wall 12 and extends forwardly therefrom. Thehood 14 has openings 18 at opposite ends thereof and a ventilating slot19 extending across the .front thereof for draining any heated airflowing therein from the firebox 13.

The firebox 13 has a forward portion designated 20 with a normally openentranceway 21. The firebox forward portion 20 is surrounded by thestuds 4 and opens inwardly of the interior surface 6 of the buildingwall 3. The firebox 13 includues a rear portion designated 22 whichextends rearwardly of the building wall exterior surface 7.

The firebox top wall 12 is spaced forwardly from the firebox back wall11 forming therewith a firebox draft opening 23 in the firebox rearportion 22. The firebox draft opening 23 communicates with a chimney 24assembly extending upwardly therefrom. The chimney assembly 24 issurrounded at the upper portion thereof by outer walls 25 spacedoutwardly therefrom and communicating at the lower ends thereof with anouter shell 26 normally extending outside the building wall on which thefireplace construction is mounted.

Secondary sheet metal walls 27, 28, 29 and 30, preferably of aluminumcoated steel, are spaced outwardly of the firebox side walls and topwall and bottom wall at the firebox forward portion 20 forming aircurrent passageways 31, 32, 33 and 34 therebetween. The framing members17 form front closure walls extending between the firebox side walls 9and the respective secondary side walls 27 and 29 to prevent forwardleakage from the passageways 31 and 33. A lip 35 extending downwardlyfrom the forward edge of the bottom wall 10 prevents air flow forwardlyfrom the passageway 34. The secondary top wall 28 has a downwardlysloping forward portion 36 which terminates adjacent the forward edge ofthe firebox top wall 12 to prevent forward flow from the air passageway32. The air current passageways 31, 32, 33 and 34 communicate with eachother whereby the air therein is free to flow completely around the firebox walls at the forward portion 20. Outer sheet metal walls 37, 38, 39and 40, preferably of aluminum coated steel, are spaced outwardly of thesecondary walls 27, 28, 29 and 30 and suitable heat insulating materialsuch as glass fiber blanket 41 is contained therebetween to furtherreduce outward heat transfer from the firebox.

Suitable elongated members in the form of angles 42 and channels 42'have one leg 43 or web 43 respectively secured, in the illustratedexample by spot welding to the exterior surface of the outer walls 37,38, 39 and 40 in spaced relation and extending longitudinally of thefircbox 13. The other leg 44 of each angle 42 and legs 44 of thechannels 4-2 extend outwardly from the exterior surface of the outerwalls and have spaced openings or slots 45 cut thereinto at respectivelystaggered positions. The legs 44 and 44 contact the opening formingmembers, in the illustrated example studs 4, supporting the fireplaceconstruction while permitting the air circulation between the outerwalls 37, 38, 39 and 4t) and the studs 4. Additional air circulation ispermitted transversely past the respective angles and channels throughthe spaced slots 45. The staggered relation between the slots 45 iSprovided to prevent the insertion by an unin formed workman, duringfireplace installation, of wooden strips or the like (not shown),transversely across the angles 42 and channels 42 in the slots whichwould block free air flow. Thus, the angles 42 and channels 42 act asspacer members for maintaining the outer walls 37, 38, 39 and 40 out ofdirect contact with the combustible studs 4 and permit free aircirculation therebetween.

In operation, a fire in the firebox 13, such as may be produced by logs46 resting on a grate 47, causes the production of hot gases and smokewhich rise toward the draft opening 23 as indicated by the arrows .8.This results in heating the firebox walls which, in turn, heat the airin the forward portion air current passageways 31, 32, 33 and 34. Thisair tends to flow generally upwardly in continuous streams fed byoutside air at 48' as indicated by the arrows 49 and produces a coolingeffect on the firebox walls. In spite of the cooling effect of the airmoving in the passageways 31, 32, 33 and 34, a measure of heat istransferred through the insulation 41 resulting in heating the outerwalls 37, 38, 39 and 40. These latter walls are spaced inwardly from thestuds 4 which support the fireplace construction by the angles 42 andchannels 42'. Air currents Stl generated by the heated outer walls 37,38, 39 and 40 are permitted to circulate and move generally upwardlybetween the outer walls and studs through the slots 45 on the respectivelegs 44 and 44. The air currents 50 may freely interchange with outsideair at the rear portions of the respective angles and channels whichopen rearwardly in the space between the outer wall 7 and shell 26. Thecurrents 50 are fed primarily at lower rear openings 51 formed betweenthe studs 4 and the lower outer wall 40; however, some air also entersat openings 52 formed between the depending lip 35 and the inner wallsurface 6 and, as noted above, free air interchange is permitted alongall the rear portions of the respective angles and channels. Thecurrents 50 discharge primarily at upper rear openings 51 between thebuilding outer wall 7 and the shell 26.

Under normal fire conditions in the firebox, the outer walls 37, 38, 39and 40 are not uncomfortably warm to the touch. When high energy fuel,however, such as charcoal is used as for barbequing, and with theconcurrent danger of a grease burn-out, abnormally high heat conditionsmay be produced for extended periods. The described support structureallows such conditions to be maintained without fire danger tocombustible building wall members.

The described fireplace construction merits approval by the mostconservative fire underwriter agencies. It is to be understood thatalthough one form of this invention has been illustrated and described,it is not to be limited to the specific form or arrangement of partsherein described and shown except insofar as such limitations areincluded in the claims.

What is claimed and desired to secure by Letters Patent 1. Aprefabricated fireplace construction adapted for mounting on a buildingwall against flammable structural means forming an opening in saidbuilding wall, said construction comprising:

(a) inner walls forming a solid fuel burning firebox, said fireboxhaving a forward portion adapted to be surrounded with said wall openingforming means and a rear portion for extending rearwardly of saidbuilding wall,

(b) outer sheet metal walls forming a part of said construction andspaced outwardly of said firebox and surrounding said firebox at saidforward portion, and

(c) spaced apart outwardly extending spacer members of relatively thincross section on the exterior surface of said outer walls and havingouter edges, said spacer members at said outer edges contacting saidopening forming means for supporting said fireplace construction whilepermitting air circulation between said outer walls and the openingforming means.

2. The construction as set forth in claim 1 wherein:

(a) said spacer members include elongated angles extendinglongitudinally of said firebox and having one leg secured to said outerwalls and the other leg extending outwardly therefrom for contacting theopening forming means.

3. The construction as set forth in claim 2 wherein:

(a) said other leg has spaced slots therealong for freedom of aircirculation transversely therepast.

4. A prefabricated fireplace construction adapted for mounting againstflammable structural means forming an opening in a building wall:

(a) sheet metal side walls and a sheet metal bottom wall and a sheetmetal back wall and a sheet metal top wall forming a solid fuel burningfirebox, said firebox having a forward portion adapted to be surroundedwith said wall opening forming means and a rear portion for extendingrearwardly of said building wall,

(b) outer sheet metal walls forming a part of said construction andspaced outwardly of said secondary walls and surrounding said firebox atsaid forward portion, and

(c) spaced apart spacer members of relatively thin cross section securedon the exterior surface of said outer walls, said spacer members havinglegs extending outwardly of said outer walls and being adapted forcontacting the opening forming means at outer edges thereof forsupporting said fireplace construction while permitting air circulationbetween said outer walls and the opening forming means.

5. The construction as set forth in claim 4 wherein:

(a) said outwardly extending legs extend longitudinally of said fireboxand each includes at least one slot therein to permit transverse aircirculation therepast,

(b) said slots being respectively staggered in transverse relation.

6. In combination, a prefabricated fireplace construction and a buildingwall, said construction being mounted against flammable structural meansforming an opening in said building wall, said construction comprising:

(a) walls forming a solid fuel burning firebox, said firebox having aforward portion surrounded with said wall opening forming means and arear portion extending rearwardly of said building wall,

(b) outer sheet metal walls forming part of said construction and spacedoutwardly of said firebox walls, and

(c) spaced apart outwardly extending elongated spacer members ofrelatively thin cross section on the exterior surface of said outerwalls, said spacer members extending longitudinally of said firebox andeach having a leg extending outwardly thereof and having an outer edge,said legs at said outer edges contacting said opening forming means forsupporting said outer walls out of contact with said opening formingmeans and forming passageways therebetween, said passageways openingrearwardly of said opening forming means permitting air interchangeabout said firebox forward portion.

References Cited by the Examiner UNITED STATES PATENTS 3/1964 Northwoodet a1. 126--120 5 FREDERICK KETTERER, Primary Examiner.

1. A PREFABRICATED FIREPLACE CONSTRUCTION ADAPTED FOR MOUNTING ON ABUILDING WALL AGAINST FLAMMABLE STRUCTURAL MEANS FORMING AN OPENING INSAID BUILDING WALL, SAID CONSTRUCTION COMPRISING: (A) INNER WALLSFORMING A SOLID FUEL BURNING FIREBOX, SAID FIREBOX HAVING A FORWARDPORTION ADAPTED TO BE SURROUNDED WITH SAID WALL OPENING FORMING MEANSAND A REAR PORTION FOR EXTENDING REARWARDLY OF SAID BUILDING WALL, (B)OUTER SHEET METAL WALLS FORMING A PART OF SAID CONSTRUCTION AND SPACEDOUTWARDLY OF SAID FIREBOX AND SURROUNDING SAID FIREBOX AT SAID FORWARDPORTION, AND (C) SPACED APART OUTWARDLY EXTENDING SPACER MEMBERS OFRELATIVELY THIN CROSS SECTION ON THE EXTERIOR SURFACE OF SAID OUTERWALLS AND HAVING OUTER EDGES, SAID SPACER MEMBERS AT SAID OUTER EDGESCONTACTING SAID OPENING FORMING MEANS FOR SUPPORTING SAID FIREPLACECONSTRUCTION WHILE PERMITTING AIR CIRCULATION BETWEEN SAID OUTER WALLSAND THE OPENING FORMING MEANS.